The present invention relates to a method and a circuit arrangement for detecting synchronization patterns in a receiver, particularly a UHF receiver (UHF=ultra high frequency) or a VHF receiver (VHF=very high frequency).
In a multitude of radio systems currently used on a UHF or VHF basis, the high-frequency signal picked up by an antenna is applied to a UHF receiver or a VHF receiver in conformity with the reception bandwidth and the reception frequency. The demodulated and digitized low-frequency signal is passed on via a data output to a connected controller unit, particularly a microcontroller unit, for further processing.
The decision whether the demodulated and digitized signal is a valid data signal or only digital noise is entirely taken by the controller unit in these conventional systems. In this respect, it is to be noted that a multitude of transmission units having the same carrier frequency is used in the frequency range of the Industrial, Scientific and Medical (ISM) bands so that the controller unit receives a multitude of additional signals which do not originate from the desired transmission unit at all.
The above-described conventional systems have in common that, fundamentally, both system components, i.e. both the UHF or VHF receiver and the controller unit must be permanently or at least predominantly operative for the reasons mentioned above. This fact is particularly a drawback in those conventional systems in which a low average current consumption is required, for example, in battery-operated conditions.